Touch event flag should control only DOM event firing.

third_party/WebKit/Source/core/input/TouchEventManager.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/input/TouchEventManager.h"
 
 #include "core/dom/Document.h"
 #include "core/events/TouchEvent.h"
 #include "core/frame/Deprecation.h"
 #include "core/frame/EventHandlerRegistry.h"
 #include "core/frame/FrameHost.h"
 #include "core/frame/FrameView.h"
 #include "core/html/HTMLCanvasElement.h"
 #include "core/input/EventHandlingUtil.h"
 #include "core/input/TouchActionUtil.h"
 #include "core/layout/HitTestCanvasResult.h"
 #include "core/page/ChromeClient.h"
 #include "core/page/Page.h"
 #include "platform/Histogram.h"
 #include "platform/PlatformTouchEvent.h"
+#include "platform/RuntimeEnabledFeatures.h"
 #include "wtf/CurrentTime.h"
 #include "wtf/PtrUtil.h"
 #include <memory>
 
 namespace blink {
 
 namespace {
 
 bool hasTouchHandlers(const EventHandlerRegistry& registry) {
   return registry.hasEventHandlers(
@@ skipping 447 matching lines @@
   }
   ~CurrentEventHolder() { m_target = PlatformEvent::NoType; }
 
  private:
   PlatformEvent::EventType& m_target;
 };
 
 WebInputEventResult TouchEventManager::handleTouchEvent(
     const PlatformTouchEvent& event,
     HeapVector<TouchInfo>& touchInfos) {
+  if (!RuntimeEnabledFeatures::touchEventAPIEnabled())
+    return WebInputEventResult::HandledSystem;

[mustaq, 2016/11/15 20:33:58]

Please return ::NotHandled.

[sunyunjia, 2016/11/16 16:39:58]

The touch event will still be triggered if we return ::NotHandled

+
   // Track the current event for the scope of this function.
   CurrentEventHolder holder(m_currentEvent, event.type());
 
   if (!reHitTestTouchPointsIfNeeded(event, touchInfos))
     return WebInputEventResult::NotHandled;
 
   bool allTouchesReleased = true;
   for (const auto& point : event.touchPoints()) {
     if (point.state() != PlatformTouchPoint::TouchReleased &&
         point.state() != PlatformTouchPoint::TouchCancelled)
       allTouchesReleased = false;
   }
 
   return dispatchTouchEvents(event, touchInfos, allTouchesReleased);
 }
 
 bool TouchEventManager::isAnyTouchActive() const {
   return m_touchPressed;
 }
 
 }  // namespace blink